In the field of this invention it is known that the UMTS specifications:
[1] 3GPP TS 23.107—3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; QoS Concept and Architecture (Release 1999)”
[2] 3GPP TS 27.007—3rd Generation Partnership Project; Technical Specification Group Terminals; [0005] AT command set for User Equipment (UE) (Release 1999)”
[3] 3GPP TS 23.057—3rd Generation Partnership Project; Technical Specification Group Terminals; Mobile Station Application Execution Environment (MExE); Functional description; Stage 2 (Release 1999) and
[4] 3GPP TS 24.008—3rd Generation Partnership Project; Technical Specification Group Core Network; Mobile radio interface layer 3 specification; Core Network Protocols—Stage 3 (Release 1999)
work on the principle that data packets for different data flows relating to specific services, are carried over separate packet sessions over the air. For example, streaming audio packets could be carried over one packet session, web browsing over another, email download over another, etc. The logic for this is that different QoS parameters (bandwidth, latency etc.) can be applied to the different services being used.
The UMTS standards [1] define 4 ‘classes’ of packet flows, based on 4 categories of applications:                Conversational class (e.g., interactive voice/video)        Streaming class (e.g., streaming media such as Internet radio, or streaming video)        Interactive class (e.g., web browsing)        Background class (e.g., email download).        
The corollary of this is that the wireless network needs to know when particular services are being used, so that it can correctly route data packets for each session over the relevant packet session over the air.
The UMTS standards imply a tight coupling between the applications and the mobile device, whereby the applications inform the mobile device (UE) that they are starting up, and what are the QoS characteristics of the traffic they will be sending/receiving. This will either be a direct, software interface in the case of integrated mobile devices as in standards [3] or can be an AT command interface as in standards [2].
However, the problem with the approach in the current set of UMTS specifications is that they require special versions of application software (email clients, web browsers, video streaming clients, etc.) to implement an (internal or external) interface to the UE. A standard PC (Personal Computer), when connected to a UE, with standard applications, will not support such an interface and therefore cannot support packet flows of different QoS for different applications, as demanded by the standards.
A need therefore exists for arrangement and method for session control in wireless communication network wherein the abovementioned disadvantage(s) may be alleviated.
Stateful inspection is an existing, well-known technology, used in Internet firewalls—a firewall blocks packets coming into or out of a network, except those explicitly allowed. Stateful inspection is a process whereby the firewall inspects packets flowing into it, implies the state of an application-specific packet session via the control packets, then allows data packets for that session to flow through the firewall, if the policy for flows of that type allow it.
The basic example of stateful inspection is the allowing through of TCP (Transmission Control Protocol) sessions originated from inside the firewall to an IP (Internet Protocol) address on the outside to be allowed, but TCP sessions from outside to be blocked—this is the mechanism that allows through web browsing and FTP (File Transfer Protocol) requests from the inside of a firewall, but blocks requests from the outside to web servers inside the firewall.
This is done by catching TCP connection request packets (packets originating from inside the firewall with the ‘SYN’ flag set), starting the TCP ‘3-way handshake’ (as explained, for example, in Chapter 18 of “TCP/IP Illustrated, Volume 1, The Protocols” authored by W. Richard Stevens and published by Addison Wesley), then opening up the source and destination IP addresses and TCP port numbers, forwarding on the packet to the outside and then monitoring the subsequent TCP control packets to ensure the connection came up and also to catch the eventual tear-down of the TCP session.
Another example of stateful inspection in firewalls for a UDP-based (User Datagram Protocol-based) service is to allow voice over IP (VoIP) calls through the firewall. In this example, incoming VoIP call-control messages are inspected and parsed to reveal the VoIP end-points (IP address and port number) and allow voice data packets through the firewall.